Last weekend I was sailing deep down wind
in fresh conditions of 25-30kts. After 10 hours my near new 12mm double braid 1st reefing line blew out seemingly due to unrecognized chafe at the boom end sheave.
It's a heavily roached fully battened main with slab reefing (luff cringle manually tied off to the gooseneck and the leach via a block attached by webbing through which the reefing line runs).
I have only recently had new sheaves made for the boom end as the older ones were a little undersized diameter wise such that the sheave now sits only 1-2mm below the slot in the boom end with the aim of avoiding any contact between the line and the metal slot. Still, given the location of the break and chafe, it appears this is where the problem lies.
I'm thinking that I should have firstly manually tied off the reefing point on the leach to the boom with a separate line both as a safety
in the event of a broken reefing line but also to bear some of the load by easing the reefing line and using it more as an outhaul
and potentially reducing the potential for chafe.
10 hours seems pretty short so I need to think this through and find a better solution.